The main goal is to develop optical biology techniques for visualizing and understanding how external stimuli, such as heat and UV irradiation, induce varieties of gene expression, and how it is related to malignant transformations in mammalian cells. We are developing a molecular reporter system by constructing plasmids containing different reporter gene GFPs (Green Fluorescence Protein) respectively. Initial studies confirm that GFP can be used as a reporter when subcloned with two different promoters, CMV and SV40. The wild type GFP and several mutants did not exhibit any detectable fluorescence when either grown in bacteria or transfected into CHO cells. However, when GFP mutant S65C was subcloned with the CMV promoter it emitted a strong green fluorescence both in bacteria and CHO cells, i.e. reporting gene expression.